234240domain: NAppears in sequencesa(n) = Sum_{d|n, n/d=1 mod 4} d^4 - Sum_{d|n, n/d=3 mod 4} d^4.at n=21A050468G.f. = Phi^5, where Phi = g.f. for A028930.at n=35A328530Triangle read by rows: T(n,k) is the number of weakly connected oriented graphs on n labeled nodes with k arcs, n >= 0, k=0..n*(n-1)/2.at n=31A350732